High resolution MR imaging of joint degeneration in the knee of the STRORT mouse

MR imaging of the knee joints of the mouse at 2.35 T produces an in-plane resolution of 35 × 70 μm and a slice thickness of 600 μm from the sagittal and coronal planes, in less than 60 min. In normal, live DBA mice, which have no known pathology, the images clearly resolve many joint structures, such as the cruciate ligaments, menisci, and articulating surfaces of the femur and tibia. Gross pathological changes were identified first in excised knees from cadaver mice of the STRORT strain. Males of this strain spontaneously exhibit rapid joint degeneration with increasing age compared to females, in which much milder symptoms develop more slowly. Thickening of the patellar tendon, displacement of the patella, deformity, and sclerosis were clearly distinguishable in males compared with females older than 7 mo of age. The same degenerative features were evident in MR images of the knees of the live male but not female STRORT mice of this age, indicating that it would be possible to monitor longitudinally by MR imaging progressive development of joint changes in this osteoarthritic model.